Organic Matter Stimulates Bacteria and Arbuscular Mycorrhizal Fungi in Bauhinia purpurea and Leucaena diversifolia Plantations on Eroded Slopes in Nepal

Erosion resulting from landslides is a serious problem in mountainous countries such as Nepal. To restore such sites it is essential to establish plant cover that protects the soil and reduces surface erosion. Mycorrhizal fungi growing in symbiosis with plants are essential in this respect because they improve both plant nutrient uptake and soil structure. We investigated the influence of organic matter and P amendment on recently produced biomass of bacteria and arbuscular mycorrhizal (AM) fungi in eroded slopes in Nepal. Eroded soil mixed with different types of organic matter or P was placed in mesh bags, which were buried around trees of Bauhinia purpurea and Leucaena diversifolia between June 2003 and December 2003 (the wet season) or between December 2003 and June 2004 (the dry season). Signature fatty acids were used to determine bacterial and AM fungal biomass after the 6‐month intervals. The amount and composition of AM fungal spores were analyzed in the mesh bags from the dry season. More microbial biomass was produced during the wet season than during the dry season. Furthermore, organic matter addition enhanced the production of AM fungal and bacterial biomass during both periods. The positive influence of organic matter addition on AM fungi could be an important contribution to plant survival in plantations on eroded slopes. Different AM spore communities and bacterial profiles were obtained with different organic amendments and this suggests a possible way of selecting for specific microbial communities in the management of eroded sites.     

Toll-like receptor and antimicrobial peptide expression in the bovine endometrium

Background  

The endometrium is commonly infected with bacteria leading to severe disease of the uterus in cattle and humans. The endometrial epithelium is the first line of defence for this mucosal surface against bacteria and Toll-like receptors (TLRs) are a critical component of the innate immune system for detection of pathogen associated molecular patterns (PAMPs). Antimicrobial peptides, acute phase proteins and Mucin-1 (MUC-1) also provide non-specific defences against microbes on mucosal surfaces. The present study examined the expression of innate immune defences in the bovine endometrium and tested the hypothesis that endometrial epithelial cells express functional receptors of the TLR family and the non-specific effector molecules for defence against bacteria.     

Saturation transfer difference NMR studies on substrates and inhibitors of succinic semialdehyde dehydrogenases

Saturation transfer difference (STD) NMR experiments on Escherichia coli and Drosophila melanogaster succinic semialdehyde dehydrogenase (SSADH, EC1.2.1.24) suggest that only the aldehyde forms and not the gem-diol forms of the specific substrate succinic semialdehyde (SSA), of selected aldehyde substrates, and of the inhibitor 3-tolualdehyde bind to these enzymes. Site-directed mutagenesis of the active site cysteine311 to alanine in D. melanogaster SSADH leads to an inactive product binding both SSA aldehyde and gem-diol. Thus, the residue cysteine311 is crucial for their discrimination. STD experiments on SSADH and NAD⁺/NADP⁺ indicate differential affinity in agreement with the respective cosubstrate properties. Epitope mapping by STD points to a strong interaction of the NAD⁺/NADP⁺ adenine H2 proton with SSADH. Adenine H8, nicotinamide H2, H4, and H6 also show STD signals. Saturation transfer to the ribose moieties is limited to the anomeric protons of E. coli SSADH suggesting that the NAD⁺/NADP⁺ adenine and nicotinamide, but not the ribose moieties are important for the binding of the coenzymes.     

Influenza A H5N1 clade 2.3.4 virus with a different antiviral susceptibility profile replaced clade 1 virus in humans in northern Vietnam

Background

Prior to 2007, highly pathogenic avian influenza (HPAI) H5N1 viruses isolated from poultry and humans in Vietnam were consistently reported to be clade 1 viruses, susceptible to oseltamivir but resistant to amantadine. Here we describe the re-emergence of human HPAI H5N1 virus infections in Vietnam in 2007 and the characteristics of the isolated viruses.

Methods and Findings

Respiratory specimens from patients suspected to be infected with avian influenza in 2007 were screened by influenza and H5 subtype specific polymerase chain reaction. Isolated H5N1 strains were further characterized by genome sequencing and drug susceptibility testing. Eleven poultry outbreak isolates from 2007 were included in the sequence analysis. Eight patients, all of them from northern Vietnam, were diagnosed with H5N1 in 2007 and five of them died. Phylogenetic analysis of H5N1 viruses isolated from humans and poultry in 2007 showed that clade 2.3.4 H5N1 viruses replaced clade 1 viruses in northern Vietnam. Four human H5N1 strains had eight-fold reduced in-vitro susceptibility to oseltamivir as compared to clade 1 viruses. In two poultry isolates the I117V mutation was found in the neuraminidase gene, which is associated with reduced susceptibility to oseltamivir. No mutations in the M2 gene conferring amantadine resistance were found.

Conclusion

In 2007, H5N1 clade 2.3.4 viruses replaced clade 1 viruses in northern Vietnam and were susceptible to amantadine but showed reduced susceptibility to oseltamivir. Combination antiviral therapy with oseltamivir and amantadine for human cases in Vietnam is recommended.     

Clinical and pathological features of six cases of sarcoidosis presenting with renal failure

Six patients with biopsy-proven renal sarcoidosis presented with renal failure of unknown origin; in none was the diagnosis of sarcoidosis initially considered. The serum creatinine concentration at the time of presentation ranged from 265 to 1380 μmol/l (3.0 to 15.6 mg/dl), with a mean of 787 μmol/l (8.9 mg/dl). Although only two patients were hypercalcemic at the time of presentation, the 24-hour urinary excretion of calcium was increased in three of the four patients in whom it was measured, and renal calculi were present in one case. Renal biopsy revealed interstitial nephritis and tubular atrophy in all cases, as well as nephrocalcinosis in three cases and noncaseating granulomas negative for acid-fast bacilli in four cases. In each patient steroid therapy led to a rapid improvement in renal function (mean post-treatment serum creatinine level 274 μmol/l [3.1 mg/dl]). The follow-up period ranged from 8 months to 8 years (mean 3.0 years). In three patients renal function remained stable with low-dose steroid therapy. In two cases recurrent hypercalcemia and deteriorating renal function accompanied steroid withdrawal but resolved with its reinstitution. In one additional case reversible deterioration in renal function accompanied tapering of the steroid dose; however, there was no hypercalcemia.This report emphasizes the importance of considering sarcoidosis in the differential diagnosis of acute renal failure of unknown origin. Long-term follow-up of such patients is essential, as relapse is common.     

Characterization of WiDr: A human colon carcinoma cell line

Summary We describe the establishment and characterization of WiDr, a cell line derived from a human colon carcinoma. It produces carcinoembryonic antigen in culture, and has a doubling time of 15 hr with plating efficiency of 51%. The HLA antigenic profile and the allozyme genetic signature (composed of eight gene-enzyme systems) of WiDr cells are different from those of HeLa cells. Furthermore, WiDr cells possess three marker chromosomes, again distinct from the HeLa marker chromosomes. Finally, it is highly tumorigenic in four different xenogeneic animal models. Based on these studies, WiDr represents a useful model cell line for tumor cell biology investigations.     

The role of oxygen radicals in dye-mediated photodynamic effects in Escherichia coli B

Photosensitive dyes representative of the thiazines, xanthenes, acridines, and phenazines mediated phototoxicity in Escherichia coli B. The observed phototoxicity was sensitizer-, light-, and oxygen-dependent and is therefore a photodynamic effect. Hydroxyl radical scavengers conferred protection against the photodynamic action of all of the representative dyes. The extent of protection was dependent on the concentration of scavenger and on the in vitro reactivity of the scavenger with the hydroxyl radical. Exogenous superoxide dismutase and catalase partially protected the cells against the dye-mediated phototoxicity, and prior induction of intracellular superoxide dismutase and catalase by growth in glucose minimal medium containing manganese and paraquat substantially protected E. coli B against the photodynamic action of all of the dyes examined. Combinations of protective treatments against the phototoxicity of all four classes of dyes, including superoxide dismutase and catalase preinduction and addition of extracellular superoxide dismutase and catalase or the addition of hydroxyl radical scavengers, provided nearly complete protection against the oxygen-dependent component of dye-mediated lethality. E. coli B grown in glucose minimal medium containing manganese and photosensitive dyes induced manganese superoxide dismutase. The extent of induction was correlated with the dyes' ability to photooxidize NADH in vitro. Thus, oxygen radicals are primarily responsible for the oxygen-dependent toxicity of the photosensitive dyes examined, and one adaptive response of E. coli B to a dye-mediated oxidative threat is to induce superoxide dismutase.     

Effects of magnesium ions on the stabilization of RNA oligomers of defined structures

Optical melting was used to determine the stabilities of 11 small RNA oligomers of defined secondary structure as a function of magnesium ion concentration. The oligomers included helices composed of Watson-Crick base pairs, GA tandem base pairs, GU tandem base pairs, and loop E motifs (both eubacterial and eukaryotic). The effect of magnesium ion concentration on stability was interpreted in terms of two simple models. The first assumes an uptake of metal ion upon duplex formation. The second assumes nonspecific electrostatic attraction of metal ions to the RNA oligomer. For all oligomers, except the eubacterial loop E, the data could best be interpreted as nonspecific binding of metal ions to the RNAs. The effect of magnesium ions on the stability of the eubacterial loop E was distinct from that seen with the other oligomers in two ways. First, the extent of stabilization by magnesium ions (as measured by either change in melting temperature or free energy) was three times greater than that observed for the other helical oligomers. Second, the presence of magnesium ions produces a doubling of the enthalpy for the melting transition. These results indicate that magnesium ion stabilizes the eubacterial loop E sequence by chelating the RNA specifically. Further, these results on a rather small system shed light on the large enthalpy changes observed upon thermal unfolding of large RNAs like group I introns. It is suggested that parts of those large enthalpy changes observed in the folding of RNAs may be assigned to variations in the hydration states and types of coordinating atoms in some specifically bound magnesium ions and to an increase in the observed cooperativity of the folding transition due to the binding of those magnesium ions coupling the two stems together. Brownian dynamic simulations, carried out to visualize the metal ion binding sites, reveal rather delocalized ionic densities in all oligomers, except for the eubacterial loop E, in which precisely located ion densities were previously calculated.     

Established human papillomavirus type 16-expressing tumors are effectively eradicated following vaccination with long peptides

Peptide-based vaccines aimed at the induction of effective T cell responses against established cancers have so far only met with limited clinical success and clearly need to be improved. In a preclinical model of human papillomavirus (HPV)16-induced cervical cancer we show that prime-boost vaccinations with the HPV16-derived 35 amino-acid long peptide E7(43-77), containing both a CTL epitope and a Th epitope, resulted in the induction of far more robust E7-specific CD8(+) T cell responses than vaccinations with the minimal CTL epitope only. We demonstrate that two distinct mechanisms are responsible for this effect. First, vaccinations with the long peptide lead to the generation of E7-specific CD4(+) Th cells. The level of the induced E7-specific CD8(+) T cell response proved to be dependent on the interactions of these Th cells with professional APC. Second, we demonstrate that vaccination with the long peptide and dendritic cell-activating agents resulted in a superior induction of E7-specific CD8(+) T cells, even when T cell help was excluded. This suggests that, due to its size, the long peptide was preferably endocytosed, processed, and presented by professional APCs. Moreover, the efficacy of this superior HPV-specific T cell induction was demonstrated in therapeutic prime-boost vaccinations in which the long peptide admixed with the dendritic cell-activating adjuvant oligodeoxynucleotide-CpG resulted in the eradication of large, established HPV16-expressing tumors. Because the vaccine types used in this study are easy to prepare under good manufacturing practice conditions and are safe to administer to humans, these data provide important information for future clinical trials.